Scanning probe microscopes (SPM's) have been known as use for a technique of measuring three-dimensional nanostructures. Of them, an atomic force microscope (AFM) is for an observation technique in which the surface of a sample is scanned with a probe having a sharpened tip while controlling the contact force to a very small value and has been used widely as a technique capable of measuring three-dimensional nanostructures to atomic order. The atomic force microscope, however, cannot measure optical properties such as reflectance distribution and refractive index distribution of the sample surface.
On the other hand, in a microminiature semiconductor device of 45 nm or less node, the application of strained silicon is expected for speedup and so, measurement of a stress distribution in a micro-region is indispensable for yield control. For further miniaturization, the condition of impurity atom distribution is required to be managed delicately at a resolution of nanometer order. Physical properties information such as the stress distribution and impurity distribution cannot be measured with the atomic force microscope or a CD-SEM (Critical Dimension Scanning Electron Microscope) used for critical dimension control. An optical measure such as Raman spectroscopy has been studied but a typical Raman spectral microscope is insufficient for spatial resolution.
Further, in order to specify causes of generation of foreign particles detected through a foreign particle inspection and of defects detected through a defect inspection, classifying of foreign particles and defects is practiced with an electron microscope called a review SEM but this measure depends on the shape and surface profile information only and so, limits the classification performance. This measure can also be expected to improve the classification performance by adding optical information but the typical optical microscope and laser scanning microscope are still insufficient for spatial resolution.
As an expedient for solving the above problems and for measuring optical properties and physical properties information of the sample surface, a scanning near-field optical microscope (SNOM) has been known. In the microscope, by scanning near-field light leaking from a micro-aperture of several 10 nm while keeping a gap between the aperture and a sample held to the identical several 10 nm (aperture probe), optical properties such as reflective coefficient and refractive index of the sample surface are measured at a resolution of several 10 nm identical to the size of the aperture which is beyond the optical diffraction limit, as disclosed in Non-Patent Document 1. As a similar method, Non-Patent Document 2 also discloses a method in which light are irradiated on a metal probe from the outside and near-field light scattered at the micro-tip portion of the probe and having a size of several 10 nm are scanned (apertureless probe).
Further, Non-Patent Document 3 describes that a surface plasmon excited on a metal surface by a micro-spotlight propagates on the metal surface.
Patent Document 1 discloses a method of forming a micro-spotlight by forming a micro-spherical lens at the tip of a fiber.
Patent Document 2 discloses a method of obtaining a micro-spotlight by filling in the interior of a carbon-nanotube either the metal carbide such as V, Y, Ta, Sb or the like which exhibits photoluminescence or electro-luminescence or a ZnS fluorescent material or a CaS fluorescent material.    Patent Document 1: JP-A-2006-515682    Patent Document 2: JP-A-2002-267590    Non-Patent Document 1: Japanese Journal of Applied Physics, Vol. 31, pp. L1302-L1304 (1992)    Non-Patent Document 2: Optics Letters, Vol. 19, pp. 159-161 (1994)    Non-Patent Document 3: Studies on Spectroscopy, Vol. 54, No. 4, pp. 225˜237 (2005)